Translucent-transparent window



March 5, 1957 o. J. SWENSON 2,783,632

TRAN$LUCENT-TRANSPARENT WINDOW Filed Aug. 25, 1950 2 Sheets-Sheet l INVENTOR. f OSCAR J. SWENSON ATT'YS March 5, 1957 o. J. SWENSON TRANSLUCENT-TRANSPARENT WINDOW 2 Sheets-Sheet 2 Filed Aug. 25 1950 FIG?) FIG.5

FIG.6

FIG.7

JNVENTOR: OSCAR J. SWENSON ATT'YS United States Patent" TRANSLUCENT-TRANSPARENT WINDOW Oscar J. Swanson, Crystal Lake, Ill.

Application August 25, 1950, Serial No. 181,388

3 Claims. (Cl. 88-60) This invention relates broadly to a method for rendering a translucent light transmitting system transparent and for rendering a transparent light transmitting system translucent. More particularly, it relates to a method for rendering a translucent light transmitting system transparent by filling void spaces within said system with a suitable liquid, and for returning said system, at will, to a condition of translucency by removing said liquid from said void spaces.

In the common use of transparent windows and walls in a building, it frequently becomes desirable or necessary to reduce their transparency to provide privacy for the occupants of the building. This change is usually accomplished by covering the transparent window or wall with shades, blinds, or drapes of opaque or semi-opaque materials. Thus the desired privacy is achieved, but only at the sacrifice of the light transmitting properties of the window or wall so covered.

Where the principal use of a window or wall requires privacy in addition to light transmission, a translucent window or wall is generally used. In many cases, how ever, clear visibility through these Walls or windows would be highly desirable at certain times.

With the introduction of the so-called picture windows, the problem of providing for light transmission, privacy, and visibility in the use of these windows has become acute. These relatively large windows are not adapted to be readily covered by a curtain or blind, but rather the general practice today is to cover the window, when privacy is desired, with a large drape of fabric. Not only. are these drapes expensive but when in the closed position, sometimes adversely affect the character of the room, and also often reduce the amount of light transmitted by the window below the amount desired.

Prior to my invention, no means were available to change a window from a condition of translucency to one I" of transparency, or vice versa, except by actually replacirig the window in question with one having the desired property, a procedure obviously impractical for making changes. for relatively short periods of use under either condition. I

l' ha ve, therefore, developed a new and novel method for alternately, and at will, and in a very simple, practical, and expeditious manner, renderinga light transmitting system transparent or translucent, thus eliminating the basic. objections, while retaining the advantages, ofboth types of fixed systems. I have also developed a translucent light transmitting system especially adapted for carrying out this method. I

ih iycinvention, therefore is the method for rendering a translucent light transmitting system transparent, comprising introducing into the system, a liquid having substantially the same index of refraction as the translucent component of the system, and, conversely, to render the ui'dfrom said system."

transmitting system particularly adapted for. carrying out said transparent system translucent by removing said liqthis method, comprising a translucent component mounted in a sealed unit, a liquid having substantially the same index of refraction as the said translucent component, and means for introducing said liquid into said unit and for removing said liquid from said unit.

The invention will be understood by reference to the following description taken in connection with the accompanying drawing in which is shown a translucent light transmitting system adapted for carrying out this invention. While have developed the system illustrated in the drawing and described below for carrying out my novel method, it is to be understood that the method is not limited to this particular system alone.

The same reference numerals have been used for the designation of like parts throughout and in the drawing.

Figure l is a front elevational, diagrammatic view of the translucent light transmitting system, with a portion broken awa to show the translucent component of the, system.

Figure 2 is a view in section taken along the line 2-2 V of Figure 1.

Figure 3 is a view in section taken along the line 33 of Figure l.

Figure is a view in section of a modification of the system shown in Figures 1, 2 and 3, taken along the line one pane of giass is plane-corrugated and is positioned between two panes of plane glass, with spaces on both sides or" said plane-corrugated pane.

Figure 7 is another modification of Figure 4 wherein a corrugated-corrugated pane of glass is positioned between two panes of plane glass, with spaces on both sides of said corrugated-corrugated pane.

Figure 8 is another modification of Figure 4 showing a monolithic structure of glass with interconnected interior voids positioned in a vertical path.

Referring to the drawings a translucent light transmitting system is illustrated which consists of a unit 10 in which a pane of translucent glass 11 having one smooth surface 12 and the other a countonred or scalloped surface 13 is arranged in spaced and substantially parallel relation to and with a pane of plane transparent glass 14. The panes of translucent glass 11 and transparent glass 14 are joined into a unit It by sealing them together around the edges by suitable mechanical means so as to produce a liquid tight joint between the two panes. in Figure 3 is shown one method of forming a mechanical seal wherein gaskets 15 are positioned between the vertical developed for attaching metal to glass can also be used for sealing the glass panes in a suitable frame.

The panes 11 and 14 are mounted in a vertical position and are separated by spacers 13 and 19 to form space 20 etween the panes i1 it. Spacers 19 are longitudinally discontinuous to prevent sealing the space between panes 11 and 14 at their top and bottom. The top of the frame members 16 is extended sufiiciently to form a header space 21 which serves to connect the space 20 and 1 all the void spaces'in the contoured surface 13 to a vacuum tube connection" 22 at the top of the unit 10. The vacuum connection 22 is connected by vacuum tube 23 to' a source of vacuum such as a vacuum pump 24, having a piston 25;

The bottom of the frame members 16 is extended belowthe, bottom edges. of panes 11 and. 14 to form a header space 26', which connects; the space 2.0, and all thevoid, spaces .of. the contoured surface. 13 to a liquid tube connection 27 at theibottom. of unit 10. The liquid tube connection 27 is connected by av tube; 2. to, the bottom of a. liquid reservoir 29, positioned. below the panes ll and. 14 in such a manner that there is an unobstructed path. for liquid to passv from the reservoir 29 into, the. space 20'and the voidsof the contoured surr cers. The vapor space 31 in the reservoir 29 is connected by tube 32 to vacuum pump 24 at a pointon thefopposite sidfe of the piston 25 from thepoint of attachment of vacuum tube 23. A vent from the vapor space.,31 to the atmosphere isprovided in cap 33, the latter. also serving-to permit addition of liquid to the reservoir 29. Thevent consists of a small hole 33a in can 33. 7

Theliguid 30 .is contained inreservoir 29 and is desirably of low viscosity, and has an optical index, of refraction substantially the same as that of the glass having the contoured surface 13. A liquid consisting of 45 parts byvolume of carbon tetrachloride and 100 parts by volume of ortho-dichlorbenzene is particularly suitable for one of the specific glass compositions used in pane 11. In the; case of the two liquids cited, carbon tetrachloride has an, index of refraction lower than most common glass compositions and ortho-dichlorbenzene has anindex of refraction higher than most common glass. Since glass with. difierent composition and different in dices; of refraction can be used for constructing pane 11. and its contoured surface 13, it is desirable and insome cascssnecessary to vary the liquid; composition from that citedto give itrarefractive index substantially the sameasQthatof the glass in the contoured surface 13. The exact proportions of carbon tetrachloride. and orthodichlorhenzene to-use in combination with a specific type ofeglassr can be determined readily by placing a small samplelof; the. glassin a test tube containing a measured amount of one of the two pure liquid cited, and; adding theother. in measured small increments, such as from a burette,. until the submerged portion; of the glass. sam: ple is no longer visible, The. proportion of the two liquids-present inthe. test tube. atrthetime thiscondition isreached is the proportion. of the two liquids which; it, isdesirable to use. to carry out the method with a unit.

containing a. pane 11 constructed. of glass having the same composition "as the sample tested in the manner described,

In. addition to having the optical properties required. forthe; method, carbon tetrachloride: and ortho-dichlor benzene are also non-flammable in character, andthus their use as described minimizes any possible fire hazard which .could result from. a broken or leaking window'ifsolids in liquids could also be used. It is thereforenot intended that the method described should-be-limited to the use of a liquid composed of carbon tetrachlorideandortho-dichlorbenzene.

The vacuum source 24 must be capable of reducing the pressure in the interior space 20 between the panes 11 and 14 sufficiently to draw the liquid 30.from:.the

reservoir 29-into said'space and up to the headerspace-22. To operatethe -above-described unit in order-.to carry out my novel methodpthe' piston 25' of vacuum. pump 24.. is pull'ed to tlieright asviewed in Figured; by-movinghandle 34 from its position at 340, indicated by the solid outline, to its position at 3411', as indicated by the dotted outline. The spring/i5 is provided as a linkage between handle 34 and piston 25 to permit the handle to be moved to position 34b rapidly and allow the piston 25 to move at a rate determined by the rate that liquid is drawn into the space 20;. The movement of the piston 25, under the impetus imparted manually to the. handle 34 and in turn by spring 45, causes a reduction in pressure within the space 20 suflicient to cause liquid 30 to flow from the reservoir 29 through liquid tube 28 into space 20: The liquid 30' fills' the space-20 and the voids or depressions and'irregularities of; the contoured surface 13 which cause the properties of translucency of pane 11. Since the liquid 30 has substantially the same refractive index as the glass with the contoured surface 13, the difiractive effect of the contoured surface 13 is neutralized or eliminated, so the. light path through the unit 10 becomes optically homogeneous, thus rendering the,

unit transparent.

Thefunction of the transparent glass pane 14 in the.

above-described drawingis merely to create a cha mber skilled in the art, that' the extent and shape of thespace or spaces within the unit for carrying out the method can be variedconsiderably and that a large number of.

alternative constructions can be used. Without intending to limit thepmethod' to only those illustrations given hereima few ofthem are cited below merely as examples.

In Ei'gur e .4 the unit 10 is composed of a pane of planetransparent glass 14 and a pane of plane-corrugated" glass 11a, which, panes are spaced apart by spacers-.18 andj19'to form space-2,0,

In, Figure, 5; the panes 14 and. 11a are. so positioned thatthe high, points of, the corrugations or scallops 35, are in contact with the, surface of pane 14 forming a. multiplicity of vertically disposed spaces or troughs. 36 which are interconnected at their upper andlower. ex-

I tremities, by header. spaces 21 and 26 respectively. The

arrangement depi'ctedin Figure 5 has a particular advantage as. will bedescribed later.

In; Figure. 6 a paneof. plane-corrugated glass 3.7 is.

positioned in spaced relationship between two panes. of.

planetransparent glass..1.4, forming two spaces 38 and 39 for liquid...

In Figure,7 is .shown a corrugatedmorrugated pane of glass 40 positioned in spaced, relationship between. two. panes ofrplane transparent. glass 14 forming spaces 41,.41.

InEigure 8 is showna monolithic. glass structure 42; withzinterior voids 43 verticallyv disposed and intercom nected. at.their upper and lower extremities by. header spaces 21 and; 26 respectively.

while the above. description. covers only the step whereby a translucent light transmitting system is;;reu--; dered transparent it is; also possible with the system de-- scribed toareturn; said system to aecondition ofi trans-.-

lucency. This is accomplished. by causing the liquid 311 partialivacuum:ismaintained in space 20,. throughout the.

draining period This possibility has an importanttpraq.

tical purpose: inconnection ,with the construction of the.

When; the; pace; between; therp n s 0i cl s- 1 nth-4E:

light transmitting material used in applying my invention is filled with a'liquid as described above, a hydrostatic pressure is created which tends to separate the said two panes confining the liquid. For this reason, it is desirable to cause the liquid 30 to flow into the space by connecting the top of said space to a source of vacuum as described above, rather than to resort to the alternative procedure of introducing the said liquid under pressure at the bottom of space 20. The vacuum causes the pressure on the exterior surfaces of the said panes to be greater than on their interior surfaces, and, as a result, the two panes deflect toward one another, In relatively small, panes this deflection is not serious. In larger panes, however, this deflection and resulting stress may be so great as to cause the panes to rupture. To solve this problem of deflection of the liquid-confining panes, I particularly recommend the structure shown in Figure 5 wherein the high points of the contoured surface 13 of the translucent pane 11 contact the surface of the opposing pane 14, to be used in combination with the procedure for introducing the liquid into the space 20 whereby a source of vacuum is connected to the top of said space, together with the procedure of controlling the rate of draining liquid 3% from the space 20 so as to always maintain a partial vacuum within said space during the draining period. By following this procedure with the construction indicated in Figure 5, the panes will always tend to deflect inwardly toward one another, but will be prevented from actually doing so by the reaction of the high points of the contoured surface 13 against the surface of the opposing pane 14, with which they are in contact. Obviously, it would be much more difficult to prevent deflection of the said panes if the forces acting on them caused them to deflect outwardly instead of inwardly. The advantage of the above-described procedure which always results in a tendency of the said panes to deflect inwardly towards one another, to permit the prevention of actual deflection in the simple and practical manner described, thus becomes apparent.

The problem of deflection of the panes as described above can be solved in another manner by using a monolithic structure of the type illustrated in Figure 8 to carry out the said novel method, since the void spaces therein can be made sufficiently small and the structure sufiiciently strong to eliminate deflection of the surfaces of the structure as a practical problem. In using the said type of structure the liquid 30 can be introduced into the said void spaces either by the application of vacuum to the top of unit 10 as described above, or the liquid 3b can be introduced into the said void spaces under pressure through tube 28 at the bottom of unit 10.

Having thus indicated a number of specific examples of constructions for carrying out my novel method, the broad range of possibilities in this connection can be indicated by the statement that the said method can be carried out in connection with any translucent light transmitting system in which the non-planar surfaces, whose diflractive etfect causes the system to be translucent rather than transparent, are so arranged that they can be flooded with a liquid having substantially the same index of refraction as the said non-planar surfaces, thus neutralizing the said diflractive efiect to render the said system transparent, and, conversely, are so arranged that the said liquid can subsequently be removed from said surfaces to restore the said system to its original condition of translucency. Thus the method is not limited to the use of panes or structures as illustrated, nor to structures of glass alone as illustrated and described, but rather can be carried out in systems constructed in a large number of configurations as well as from a large number of clear light transmitting materials, another example other than glass being the various organic chemical plastics now available.

From the above description, it will readily be appreciated that my novel method now makes it possible to portant and useful purpose.

Because of the increasing usage of light transmitting structures, such as picture windows, in external construc-' tion of buildings, and light transmitting walls in interior construction, both with inherent disadvantages eliminated by my invention, my novel method becomes particularly important and useful, and in addition offers opportunities for application of light transmitting systems in a manner heretofore not possible.

The invention is hereby claimed as follows: i

1. A light-transmitting structural window unit comprising at least two opposed substantially parallel sheets of a light-transmitting material arranged to form a window and mounted in a unit sealed along the edges of the sheets, the outer said sheets each having a smooth planar transparent outer surface, one of said sheets having at least one inner surface which is continuously scalloped throughout the light-transmitting area of said window to alone render the window normally translucent and incapable of transmitting a clear image, the high points of said scalloped surface contacting the sheet opposite thereto but the latter and the scalloped sheet not being united in the light-transmitting area of said window, thereby preventing deflection of said scalloped sheet and said opposite sheet towards each other, spaces being formed between said scalloped sheet and said opposite sheet corresponding to the troughs on said scalloped surface and between said high points, means for applying a vacuum to said spaces to introduce thereinto a transparent liquid having substantially the same index of refraction as the material from which said scalloped surface is composed, whereby said window is rendered transparent, and means for removing said liquid from said spaces, whereby said window becomes translucent.

2. A light-transmitting structural window unit comprising two opposed substantially parallel sheets of a lighttransmitting material arranged to form a window and mounted in a unit sealed along the edges of the sheets, each said sheet having a smooth planar transparent outer surface, the inner surface of one of said sheets being continnously scalloped throughout the light-transmitting area of said window to alone render the window normally trans lucent and incapable of transmitting a clear image, the high points of said scalloped surface contacting the other said sheet but the sheets not being united in the lighttransmitting area of said window, thereby preventing deflection of said sheets towards each other, spaces being formed between said sheets corresponding to the troughs on said scalloped surface and between said high points, means for applying a vacuum to said spaces to introduce thereinto a transparent liquid having substantially the same index of refraction as the material from which said scalloped surface is composed, whereby said window is rendered transparent, and means for removing said liquid from said spaces, whereby said window becomes translucent.

3. A light-transmitting structural window unit comprising a plane transparent glass window pane in opposed contacting substantially parallel relationship with a planecorrugated translucent glass window pane, said panes being arranged to form a window and mounted in a unit sealed along the edges of the panes, the inner surface of said plane-corrugated window pane being continuously corrugated throughout the light-transmitting area of said window to alone render the window normally translucent and incapable of transmitting a clear image, the high points of said corrugated surface contacting said plane window pane but the panes not being united in the lighttransmitting area of said window, thereby preventing deflection of said panes towards each other, spaces being formed between said panes corresponding to the troughs om said 'porrugated surface and between said h1g1; ppints, a jransparent' Liquid in said spaces" having, substantially" the-same index of refraction as saidplaiie-eorrugated" window pane, means fibr'applyi'ng avacuum to said spaees to introduce said liquid thereinfcdmvhereby said Window isrrendeied transparent, and} means for remcving said liquidfrom said'sp-aces, whereby said window becomes translucent;

References. Cited in the fil'eof thisLpate'nc' UNITED STATES PATENTS.

A u Hyde Aug, 25, 1936- ertel May 6, 1941 Beck et a1 Mar. 10, 1942 Bond June30, 194'4 Wolkenhauer Apr. 10, 1945' Solis June 19, 1945 Winn Apr; 13, 1948' Aparicio June 28, 1949' Lacy etal. May 13, 1952 De- Lisio Sept. 30, 1 952 FOREIGN PATENTS Germany Oct. 8; 1912' Great. Britain lune 19, 1922 Great Britain July 21', 1932 

